Agricultural seed planters typically produce one or more furrows, or narrow grooves made in the ground, for planting seeds in rows. Upon producing a furrow, the seed planter will typically meter and deposit seeds into the furrow at approximate intervals to balance a maximum number of plants in a planting row with a minimum spacing between plants for optimal growth and harvesting.
Upon depositing seeds in a furrow, seed planters will typically drag soil from behind to close the furrow using a soil closing system. Then, seed planters will typically press the dragged soil downward, onto the covered furrow, using a soil pressing system, in order to maximize contact between deposited seeds and soil and ensure soil stability for plant growth.
The depth at which an opener, such as a disc or other ground engaging tool, penetrates into the field and cuts the furrow may be controlled, for example, by a gauge wheel. The position of the gauge wheel is typically set by rotating a lever or control arm to one of a series of depth setting positions. While the gauge wheel sets the penetration depth for the opener, a down pressure system, which typically includes a hydraulic cylinder, applies a down force on the opener to ensure that the opener penetrates into the ground. For most planters, the amount of down force can be adjusted by the operator to accommodate different soil conditions. Due to factors that affect seeding performance, such as rocks, obstacles, saline areas, and the like, it is a challenge to substantially maintain a constant seeding depth while traveling at various speeds.
What is needed is an improved down pressure control system for automatically and continually adjusting the down pressure applied to one or more openers in response to changes in soil conditions to maintain a relatively constant penetration depth so that the one or more openers may cut an elongated trench in the soil at a substantially constant depth at various speeds.